Early life experiences play a critical role in shaping behavior. From birth to two years of age, brain and behavioral development are continuously and interdependently influenced by environmental characteristics. Yet little is known about early genetic, environmental and neural correlates of emotion regulation (ER). The overarching goal of this research is to identify developmental mechanisms at play in children?s early regulatory abilities as precursors of later internalizing an externalizing behavior problems. The project builds on two previously funded NIMH studies (R37 MH50560, PI: Goldsmith; P50 MH100031, Center Director and PI: Davidson) conducted at the University of Wisconsin?s Waisman Center, an interdisciplinary research center optimally positioned to support the PI?s career development. The first goal of the project is to study extensive measures of ER in a sample of twins at 6, 12, 22, and 36 months of age to detect the relative genetic and environmental contributions to ER across infancy. Sensitive parenting, familial stress, and parent involvement all impact infants? behavioral ER, yet the extent to which ER is related to hereditary versus environmental mechanisms of influence is unknown. The project will identify discrete parenting and family environmental moderating mechanisms associated with ER development. The second goal of the project is to examine how early structural and functional alterations within the limbic system impact behavioral phenotypes of emotion regulation. Emerging findings in neurobehavioral science suggest that brain and behavioral development are interdependent and that infancy is a pivotal time in the development of both ER and the neural circuitry within the limbic system and basal ganglia. Each of these systems play a pivotal role in emotional expression and regulation, yet we do not know how neurodevelopment of ER during infancy may be altered by environmental factors. The project examines measures of ER and parenting from 1 to 24 months to better understand interrelations between neurodevelopment and infants? developing regulatory abilities. The goals of the proposed project mirror those that NIMH recently published examining the development of affective behaviors and prioritizing support for research elucidating genetic, biological, behavioral and environmental mechanisms in developing complex social behaviors. The proposed training plan incorporates formal and informal instruction in statistical genetics, affective neuroscience, and statistical analysis of neuroimaging from leaders in the field. The PI will acquire the necessary training, practical experience, and knowledge to move into a tenure-track faculty position at a strong research institution.